NuBenz

Mercedes recommends 26/32 psi f/r for <100mph and 29/35 psi f/r for >100mph.

I finally got around to checking my tire pressures with my trusty gauge... my tires were all over the place, thanks to the dealer. The highest pressure I noted was 39 psi on the right front tire. I never did understand how a brand new car could be delivered to the customer with the tire pressures all out of whack! The same overpressurization is also common with Porsche. They apparently pump up the tires for the long ship haul over to the states, probably to help reduce deflation issues and flat spotting.

After "normalizing" my tires to 26/32, the TPMS (tire pressure monitoring system) warned, "Low pressure right front and left front!" 32 psi in the rear did not alarm the TPMS.

To make a long story short, the TPMS needs to be RESET after changing tire pressures to relearn its proper pressure range to monitor. The RESET is accomplished by holding down the little dimmer knob to the left of the gauge cluster when viewing the TPMS screen.

Now that I reset the system, it has worked flawlessly. And thanks to you all, I can monitor static pressures with the key in the ignition.

etenn

Someone else just posted somewhere that the proper pressure for highway driving should be 28/33...not that there is a large difference, but which is best for long distance (70-90 mph) highway driving?

Ed

mkassab

etenn,

I agree, I always run a few psi over dealer recommended....
I run 28/33 as you stated. Mark
btw, I also took my tires off and had them rebalanced. All 4 need weight opposite the valve stem. Note, I said I took them off, this way I control the situation and remount the wheels to proper torque. I bought the life time balance from Goodyear. Can get them balanced as often as you like. I'll do every 5000 miles when I rotate.

NuBenz

Such as the type of tire, profile, suspension setup, and application (as in touring versus tracking).

Higher tire pressures in general should stiffen the sidewall and potentially give the driver more feedback at the steering wheel as to what the car is doing. However, higher tire pressures also lead to a "rougher" ride and may decrease the size of the contact patch, thus potentially reducing overall grip.

With low-profile tires, you can run lower pressures with little sacrifice in steering feel or response due to the stiff, low-profile sidewalls. At the same time, you increase the size of the contact patch on the road. Experimenting out on the track with different tire pressures makes a significant difference in handling.

The Continental SportContact 2 tires on my E500 have a max rating of 51 psi. Mercedes
recommends 26/32 f/r on the inside of my gas lid. Are the same pressures printed on all E's (320 vs 500, sport vs non-sport)?

Anyhow, 26 psi is really low. I'm sure they recommend this for the comfort factor. I'm still experimenting with the Benz, but I'll probably go with 29/35 psi as recommended for >100 mph, and use this as my usual pressures. I may even go a little higher in the front to get a little more bite on turn in...

We'll see. Your choice of 28/33 is completely reasonable. I run 34/42 on my p-car out at the track which is 2 psi below factory recommended specs. GT-3 racing specs are even lower than that.